Title: PLUTO for RADARSAT2
1PLUTO for RADARSAT-2 Operations
Mark Seymour Space Missions Group
2Overview of RADARSAT-2
- Commercial C-Band SAR mission - 2005 launch
planned - Alenia PRIMA Bus - COP-1 compliant
- Packet-based TC TM as per ESA PSS-05
- Will be owned and operated by MacDonald
Dettwiler - Two Canadian Ground Stations for routine
operations one external site (Svalbard) to
support LEOP - Low Earth, sun-synchronous dawn-dusk orbit
- 2 Canadian sites cover lt 9 of orbit cycle - 16
when Svalbard used - 13 out of every 20 routine orbits have a pass
- Average pass duration 10 minutes - inter-pass
gaps up to 8.5 hours
3Factors influencing ops concept
- In-flight operations costs are a concern - need
to make efficient use of staff resources and time - Short and infrequent passes preclude solely
manual spacecraft control - High telecommand uplink volume to support
nominal imaging activities - Time-critical and complex activities during LEOP
- Desire to minimise potential for operator error
and reduce workload - Fewer spacecraft engineering personnel available
at Control Centre during routine operations phase - Autonomous on-board FDIR does ease Ground
workload but must be monitored and accounted for
4The Control System solution
- SCOS-2000 chosen for Control System (SCS-CA)
- MDA developed in-house Spacecraft Planning
Subsystem - RADARSAT-2 specific upgrade of Automatic
Scheduling Execution (called RASE) - Implements Draft 5 of PLUTO (Procedure Language
for Test and Operations) under development by the
ECSS - RASE provides the PLUTO procedure scripting and
execution environment - PLUTO enables autonomous operations using
features similar to STOL and TESLA
5Benefits of PLUTO for R-2 Ops
- decreased likelihood of Operator error
- increased confidence in procedure success
- minimisation of procedure execution duration
- consistency and repeatability of procedures
- powerful interface to SCOS-2000
- rapid calculations and analysis of TM values
- PLUTO procedures can be scheduled by Planning
System for pre-planned passes driven by Planning
System inputs - potential for a future PLUTO Users community
sharing ideas and suggesting upgrades to language
capabilities
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8RASE Space System Model
- RASE environment maintains real-time knowledge of
the Ground and Space Segments through the SSM,
updated by telemetry and other status values
supplied by SCOS-2000. SSM elements hold distinct
pieces of information.
9TC TM in the SSM
10MISCconfig in the SSM
11Procedure Development Environment
- Jext PLUTO script editor, with some MDA
customisations - dedicated tags used for procedure documentation
- enables SSM element references to be inserted
- recognises and colourises PLUTO keywords, text
strings, functions etc - PLUTO script is compiled and checked for syntax
errors - Executable is consistency-checked against SSM
for - gt TC and TM identifiers consistent with SSM
- gt correct type usage of PLUTO variables
- gt correct number type of TC parameters
- final procedure is stored under an integrated
configuration control system
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13The SSM Consistency Check
14The Procedure Execution Environment
15Anatomy of a PLUTO procedure
16Other PLUTO features
- PLUTO provides many of the features expected in
high-level computing languages, including - logical checks (if .. then, in case)
- Boolean operators (AND, OR, XOR)
- looping (repeat...until, repeat...while,
for...do) - arithmetic and string functions
- logging of information alarm messages to
SCOS-2000 - user interaction (ask user)
- procedure flow control (initiate parallel step,
resume at step) - read and write of SSM elements (assigning
variables from TM, setting MISCconfig values
contained in SSM elements) - system calls, file operations
17RADARSAT-2 extensions
- Additional capability was added to PLUTO RASE
to meet RADARSAT-2 requirements - Ability to specify command execution time -
support for time tagged commands - Ability to specify the stage of command
acknowledgement which constitutes successful
execution (i.e. anything from successful
transmission to successful execution verification
in TM) - Integrated PLUTO procedure file configuration
control
18RADARSAT-2 usage of PLUTO
- Payload AIT run high-level P/L tests with
complex command structures via SCS-CA rather than
the EGSE - State of Health checks rapidly analyse hundred
of TM parameters and provide a summary result to
the Operator - LEOP Operations conduct critical and
time-sensitive operations such as deployments
using the ability to rapidly send out commands
and analyse the results, then taking decisions
based on these results - Unit Commissioning take a subsystem from
power-on through commissioning checks in
real-time matching the responsiveness of the unit
19RADARSAT-2 usage of PLUTO
- Routine Operations use repeatable PLUTO
procedures for routine real-time tasks, scheduled
by the Spacecraft Planning Subsystem - Backorbit TM processing initiation and analysis
of playback telemetry, and summary of results - S/C Trending generate reports of long-terms
trends in telemetry values and calculate
suggested tuning of on-board parameters as a
result
20Other possible uses
- Initial contingency reaction quick diagnosis of
failures detected in telemetry, and sending of
any telecommands required to access further data - Background spacecraft maintenance monitor for
non-critical s/c conditions and react
accordingly, for example emptying memory areas
before they become full - Spacecraft reconfiguration use telemetry to
mirror the status of a prime unit onto the backup
unit and perform the switch-over, for instance
heater group switch-over
21Possible lights-out scenario
- Unstaffed pass, both Control Centre and Ground
Station - SPS has pass planning information including
Ground Station ID, AOS and LOS times, activities
to be performed, predicted state of spacecraft - SPS generates RASE schedule for each pass
- Schedule calls nominal PLUTO procedures and
provides pathways to contingency recovery
procedures - Schedule and procedures are robust in checking
for preconditions, health of spacecraft and
success of operations - External system calls from RASE used to page /
e-mail on-call engineers in the event of alarms?
22The reality
- PLUTO procedures will be executed in RASE under
Operator supervision to perform some LEOP
operations - PLUTO procedures will also be developed for
infrequent nominal and contingency procedures - No autonomy enabling remote Ground Station
control - SPS planning of routine activities will use a
mixture of pre-canned TC Lists and schedules of
PLUTO procedures - Contingency analysis recovery operations will
require real-time Spacecraft Engineering support - Currently no plans for unstaffed passes. The
viability and safety of the lights-out scenario
for routine operations would have to be
demonstrated to a high degree of confidence
before this could be considered.
23Next steps in RADARSAT-2 Operations Development
- A PLUTO flight procedure development guide has
been written - Coding of preliminary PLUTO flight SVT
procedures is underway - Operations Database population is underway
validation during SVTs - Refinement of SSM template to effectively
organise information imported from ODB - Existing concepts will be revised as more is
learnt about the capabilities of RASE, PLUTO and
the spacecraft itself - New uses for RASE / PLUTO will become apparent
as the mission progresses towards launch - All PLUTO procedures will be extensively
validated during SVTs and Simulations campaigns
24The future of PLUTO
- The concept of semi-autonomous operations using
PLUTO is challenging, yet promises to bring
rewards in terms of operations efficiency and
reliability, improved safety and a reduction in
Operator workload and operations costs. - The PLUTO language is not mission or Ground
System specific and would suit a variety of
Ground and in-flight applications. ASE could be
adapted to work with other Control Systems. -
- RADARSAT-2 is one of the first missions to use
PLUTO - it is hoped other missions can benefit
from the experience and further extend the
concept.